Effects of Wheat Flour Milling Method on Glycemic Response and Gastrointestinal Symptoms

The goal of this clinical trial is to learn if the way wheat flour is ground - by stone milling (an older method) or roller milling (used for most flour today) - changes blood sugar levels after eating bread, in healthy adults aged 20 to 40 who eat bread regularly. The main questions it aims to answer are: Does bread made from stone-milled flour cause a smaller rise in blood sugar after breakfast than bread made from roller-milled flour? Does the milling method change stomach symptoms such as bloating? Researchers will compare bread made from stone-milled wheat flour to bread made from roller-milled wheat flour, made from the same wheat and prepared the same way, to see if milling method changes blood sugar and stomach symptoms. Participants will: Eat the study bread at breakfast and lunch for 3 days, then switch to the other bread for 3 days, in a random order Eat a standard bread for a few days before each 3-day period Wear a small sensor that tracks blood sugar day and night for 14 days Keep a daily food diary, including photos of meals Answer online questionnaires about stomach symptoms

Inclusion Criteria: * BMI 18.5-25 kg/m2 * Healthy, defined by reference to the exclusion criteria below * Habitual consumption of bread on most days, at more than one meal per day * Willing and able to consume the study breads, to follow the standardized meal pattern for 14 days, and to wear a CGM sensor continuously for 14 days Exclusion Criteria: * Smoking/tobacco use * Any disease or condition or use of drugs or other compounds or treatments that could have a clinically significant impact on energy metabolism and/or gastrointestinal health (Roma IV to rule out IBS) * Diagnosed diabetes mellitus of any type (no screening measure of glycemic status will be obtained because sample collection is minimized within the project resources) * Diagnosed celiac disease, or self-reported gluten or wheat sensitivity leading to habitual avoidance of wheat products * Pregnancy or lactation * Systemic antibiotic use within 4 weeks before the calibration visit * Night-shift or rotating-shift work during the study period * Skin condition at the sensor site precluding CGM wear * No allergies to wheat/grains